// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2006-2008 Benoit Jacob <jacob.benoit.1@gmail.com>
// Copyright (C) 2009 Ricard Marxer <email@ricardmarxer.com>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#include "main.h"
#include <iostream>

using namespace std;

template<typename MatrixType>
void
reverse(const MatrixType& m)
{
	typedef typename MatrixType::Scalar Scalar;
	typedef Matrix<Scalar, MatrixType::RowsAtCompileTime, 1> VectorType;

	Index rows = m.rows();
	Index cols = m.cols();

	// this test relies a lot on Random.h, and there's not much more that we can do
	// to test it, hence I consider that we will have tested Random.h
	MatrixType m1 = MatrixType::Random(rows, cols), m2;
	VectorType v1 = VectorType::Random(rows);

	MatrixType m1_r = m1.reverse();
	// Verify that MatrixBase::reverse() works
	for (int i = 0; i < rows; i++) {
		for (int j = 0; j < cols; j++) {
			VERIFY_IS_APPROX(m1_r(i, j), m1(rows - 1 - i, cols - 1 - j));
		}
	}

	Reverse<MatrixType> m1_rd(m1);
	// Verify that a Reverse default (in both directions) of an expression works
	for (int i = 0; i < rows; i++) {
		for (int j = 0; j < cols; j++) {
			VERIFY_IS_APPROX(m1_rd(i, j), m1(rows - 1 - i, cols - 1 - j));
		}
	}

	Reverse<MatrixType, BothDirections> m1_rb(m1);
	// Verify that a Reverse in both directions of an expression works
	for (int i = 0; i < rows; i++) {
		for (int j = 0; j < cols; j++) {
			VERIFY_IS_APPROX(m1_rb(i, j), m1(rows - 1 - i, cols - 1 - j));
		}
	}

	Reverse<MatrixType, Vertical> m1_rv(m1);
	// Verify that a Reverse in the vertical directions of an expression works
	for (int i = 0; i < rows; i++) {
		for (int j = 0; j < cols; j++) {
			VERIFY_IS_APPROX(m1_rv(i, j), m1(rows - 1 - i, j));
		}
	}

	Reverse<MatrixType, Horizontal> m1_rh(m1);
	// Verify that a Reverse in the horizontal directions of an expression works
	for (int i = 0; i < rows; i++) {
		for (int j = 0; j < cols; j++) {
			VERIFY_IS_APPROX(m1_rh(i, j), m1(i, cols - 1 - j));
		}
	}

	VectorType v1_r = v1.reverse();
	// Verify that a VectorType::reverse() of an expression works
	for (int i = 0; i < rows; i++) {
		VERIFY_IS_APPROX(v1_r(i), v1(rows - 1 - i));
	}

	MatrixType m1_cr = m1.colwise().reverse();
	// Verify that PartialRedux::reverse() works (for colwise())
	for (int i = 0; i < rows; i++) {
		for (int j = 0; j < cols; j++) {
			VERIFY_IS_APPROX(m1_cr(i, j), m1(rows - 1 - i, j));
		}
	}

	MatrixType m1_rr = m1.rowwise().reverse();
	// Verify that PartialRedux::reverse() works (for rowwise())
	for (int i = 0; i < rows; i++) {
		for (int j = 0; j < cols; j++) {
			VERIFY_IS_APPROX(m1_rr(i, j), m1(i, cols - 1 - j));
		}
	}

	Scalar x = internal::random<Scalar>();

	Index r = internal::random<Index>(0, rows - 1), c = internal::random<Index>(0, cols - 1);

	m1.reverse()(r, c) = x;
	VERIFY_IS_APPROX(x, m1(rows - 1 - r, cols - 1 - c));

	m2 = m1;
	m2.reverseInPlace();
	VERIFY_IS_APPROX(m2, m1.reverse().eval());

	m2 = m1;
	m2.col(0).reverseInPlace();
	VERIFY_IS_APPROX(m2.col(0), m1.col(0).reverse().eval());

	m2 = m1;
	m2.row(0).reverseInPlace();
	VERIFY_IS_APPROX(m2.row(0), m1.row(0).reverse().eval());

	m2 = m1;
	m2.rowwise().reverseInPlace();
	VERIFY_IS_APPROX(m2, m1.rowwise().reverse().eval());

	m2 = m1;
	m2.colwise().reverseInPlace();
	VERIFY_IS_APPROX(m2, m1.colwise().reverse().eval());

	m1.colwise().reverse()(r, c) = x;
	VERIFY_IS_APPROX(x, m1(rows - 1 - r, c));

	m1.rowwise().reverse()(r, c) = x;
	VERIFY_IS_APPROX(x, m1(r, cols - 1 - c));
}

template<int>
void
array_reverse_extra()
{
	Vector4f x;
	x << 1, 2, 3, 4;
	Vector4f y;
	y << 4, 3, 2, 1;
	VERIFY(x.reverse()[1] == 3);
	VERIFY(x.reverse() == y);
}

// Simpler version of reverseInPlace leveraging a bug
// in clang 6/7 with -O2 and AVX or AVX512 enabled.
// This simpler version ensure that the clang bug is not simply hidden
// through mis-inlining of reverseInPlace or other minor changes.
template<typename MatrixType>
EIGEN_DONT_INLINE void
bug1684_job1(MatrixType& m1, MatrixType& m2)
{
	m2 = m1;
	m2.col(0).swap(m2.col(3));
	m2.col(1).swap(m2.col(2));
}

template<typename MatrixType>
EIGEN_DONT_INLINE void
bug1684_job2(MatrixType& m1, MatrixType& m2)
{
	m2 = m1;			   // load m1/m2 in AVX registers
	m1.col(0) = m2.col(3); // perform 128 bits moves
	m1.col(1) = m2.col(2);
	m1.col(2) = m2.col(1);
	m1.col(3) = m2.col(0);
}

template<typename MatrixType>
EIGEN_DONT_INLINE void
bug1684_job3(MatrixType& m1, MatrixType& m2)
{
	m2 = m1;
	Vector4f tmp;
	tmp = m2.col(0);
	m2.col(0) = m2.col(3);
	m2.col(3) = tmp;
	tmp = m2.col(1);
	m2.col(1) = m2.col(2);
	m2.col(2) = tmp;
}

template<int>
void
bug1684()
{
	Matrix4f m1 = Matrix4f::Random();
	Matrix4f m2 = Matrix4f::Random();
	bug1684_job1(m1, m2);
	VERIFY_IS_APPROX(m2, m1.rowwise().reverse().eval());
	bug1684_job2(m1, m2);
	VERIFY_IS_APPROX(m2, m1.rowwise().reverse().eval());
	// This one still fail after our swap's workaround,
	// but I expect users not to implement their own swap.
	// bug1684_job3(m1,m2);
	// VERIFY_IS_APPROX(m2, m1.rowwise().reverse().eval());
}

EIGEN_DECLARE_TEST(array_reverse)
{
	for (int i = 0; i < g_repeat; i++) {
		CALL_SUBTEST_1(reverse(Matrix<float, 1, 1>()));
		CALL_SUBTEST_2(reverse(Matrix2f()));
		CALL_SUBTEST_3(reverse(Matrix4f()));
		CALL_SUBTEST_4(reverse(Matrix4d()));
		CALL_SUBTEST_5(reverse(
			MatrixXcf(internal::random<int>(1, EIGEN_TEST_MAX_SIZE), internal::random<int>(1, EIGEN_TEST_MAX_SIZE))));
		CALL_SUBTEST_6(reverse(
			MatrixXi(internal::random<int>(1, EIGEN_TEST_MAX_SIZE), internal::random<int>(1, EIGEN_TEST_MAX_SIZE))));
		CALL_SUBTEST_7(reverse(
			MatrixXcd(internal::random<int>(1, EIGEN_TEST_MAX_SIZE), internal::random<int>(1, EIGEN_TEST_MAX_SIZE))));
		CALL_SUBTEST_8(reverse(Matrix<float, 100, 100>()));
		CALL_SUBTEST_9(reverse(Matrix<float, Dynamic, Dynamic, RowMajor>(
			internal::random<int>(1, EIGEN_TEST_MAX_SIZE), internal::random<int>(1, EIGEN_TEST_MAX_SIZE))));
		CALL_SUBTEST_3(bug1684<0>());
	}
	CALL_SUBTEST_3(array_reverse_extra<0>());
}
